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. A. C. ENGERT. ,Device for Refraoting, Reinforcing,

and Modulating Sound.

Patented Aug. 17,1880.

Fig. 5.

Fig. 2.

t r 8 6 9 E .9 T a R .W N z m m M w w llll m n a 21K h & m IHL 4 W N. PETERS, PHOTO-LITHQGRAPHER, WASHINGTON. D\C.

UNITED STATES PAT NT OFFICE.

ADAM O. ENGERT, OF BROMLEY-BY-BOW, ENGLAND.

DEVICE FOR REFRACTING, RE-ENFORCING, AND MODULATING SOUND.

SPECIFICATION forming part of Letters Patent No. 231,292, dated August 17, 1880.

Application filed September 8, 1879.

To all whom it may concern:

Be it known that I, ADAM OYnUs ENGERT, of Bromley-by-Bow, in the county of Middlesex, England, have invented new and useful Improvements'in Means used for Refracting, Re-enforcing, and Modulating Sound, which improvements are fully set forth in the following specification, reference being had to the accompanying drawings.

This invention has for its object to furnish improved means for refracting, re-enforcing, and modulating sound.

For refractin g, re-enforcin g, and modulating sound in the interior of buildingsas, for eX- ample, in churches or concert-roomsI suspend or secure thin sheets of steel or other hard metal or material to the walls on the inside of the building, or suspend such plates from frame-works or stands erected for the purpose. Each plate has two pins, strips, or coiled or other springs of metal attached to it at different points, and is by these secured to the wall or stand; or it might be supported from the wall or stand by a single pin, strip, or spring. i

Plates supported by pins or springs in the above manner can also be applied to musical instruments-as, for example, to pianos-and be held in them either in a horizontal or vertical position. For a vertical piano the plates might, for example, be placed at the back or upper part of the front of the frame or case of the instrument, and two, three, or more plates might be used, one in front of the other, at a slight distance apart, while for a horizontal piano the plates might be either at the top, above the strings, or in the lower part of the ease, below them, sustained by any desired number of springs. Similar plates may also be applied to organs.

Plates carried in the above manner by stands can, in like manner, be employed in the open air; or I employ a sheet of hard metal coiled up into a spiral coil or scroll and placed within a rectangular or other tubular casing, the outermost coil of the scroll being attached to the interior of the casing, and such casings, with the coiled plates within them, may be placed in different parts of the building, wherever it may be required to use them. The

sides of the casing may also have openings Patented in England June 7, 1878.

formed through them. Flat or slightly-curved sheets or plates of metal may similarly be placed within a casin g, and be carried, in the manner hereinbefore described, by strips or springs or pins from the side of the casing. Scrolls formed from metal plates may also be used without the casing, and be secured by the outermost coils to the walls of the building or to frames or stands.

The drawings hereunto annexed show examples of plates suspended in the manner above described from the inner face of the wall of a building.

Figure 1 shows an edge view, and Fig. 2 a face view, of a plate sustained by springs at a short distance from the face of awallit may be the interior of a church, concertroom, or other building where it is desirable that speaking or singing shall be clearly heard in every part of the building. Any desired extent of the surface of the wall of the building may thus have plates mounted in front of them, according to the effect required to be produced. The plates also need not be mounted upon the wall of the building. They might be mounted at other parts of its interior, or upon frames or stands provided for the purpose. The plates also may either be flat or, as I prefer, slightly curved.

The plates should be placed at that part or parts of the building near which is produced the sound which itis desired to resound through the building, while at the other parts of the building provision may be made for preventing the re-echoing of any sound made near them.

In Figs. 1 and 2, A is part of the wall of the building. B B are two coiled springs, or it might be strips of metal, secured to the wall, and also to the plate 0, which may be of iron or steel, or other hard metal or material. G G are other very light springs for keeping the plates in position away from the wall.

In some cases a second plate, 1), may similarly be carried by springs E from the plate G, as shown at Fig.3. The springs E are, by preference, so placed that a line drawn between them shall be at right angles to a line drawn between the springs B.

When two or more plates are used, one in front of the other, I make the plates one 2 cameos smaller than the other, as shown at- Figs. 4, 5, and 6, and at Fig. 7. The plates shown at Figs. 4, 5, and 6 are supported by two pins near their lower edge, and between the plates distance-pieces are mounted on the pins, to keep the plates apart and allow of them being all firmly clamped together. The plates shown at Fig. 7 are similarly supported by two pins near the edge of one of their longer sides.

Whenever the plates hang down or stand up from the springs or pins that carry them the plates, if made of thin metal or material, should be slightly curved in the manner shown at Fig. 6; but when stout plates are used it is not necessary to bend them.

Fig. 8 shows a plate supported by a single spring at its center. Fig. 9 shows, as a modification of my apparatus, a coiled plate, A, placed within a cylindrical or other shaped casing, B, the outer edge of the coiled plate being secured to the interior of the casing by springs O. Such coiled plates, however, might be used without any protecting casin g, and be secured to any part of a building or elsewhere, wherever it is desired to reverberate sound.

In many cases it is desirable that provision should be made for arresting at times the ac tion of the rei'erbcratory plates. This may be 1. The hereinbefore-described apparatus for retracting, re-ent'orcing,and modulating sound, consisting essentially of the combination, with the plate 0, of the main or supporting springs and the light or steadying springs, as described.

2. The combination, with the walls of a building, of a series of souinl-retracting devices, each consisting of one or more hard metallic plates, the main or supporting springs, and the light or steadyiug springs, substantially as hereinbefore set forth.

London, August 25, 1879.

ADAM CYRUS ENGERT.

Vitnesscs GEO. J. B. FRANKLIN, J. WATTS, Both clerks to Messrs. Harrison Broth-H's, Notaries Public, 17 Graeeehureh Street, London, E. O. 

